This project proposes to continue our efforts to investigate the role of autoimmune response to collagen in the pathogenesis of connective tissue diseases. Studies are planned to elucidate further the immunologic mechanisms responsible for the induction of arthritis in rats or mice immunized with type II collagen. Additional studies will seek to determine whether this model can be used to delineate new therapeutic modalities which may be applicable to the treatment of rheumatic diseases in humans. Finally, this project proposes to continue the clinical and immunologic evaluations of patients with severe rheumatoid arthritis treated by total lymph node irradiation.